San Carlos, CA, and New Haven, CT – June 14, 2018 – Apexigen, Inc., and Yale Cancer Center today announced
a clinical trial collaboration to evaluate Apexigen’s APX005M in combination
with cabiralizumab and Opdivo
in patients with advanced solid tumors. The Phase 1/2 clinical trial will evaluate
the safety, tolerability, and preliminary activity of APX005M in combination with
cabiralizumab and Opdivo in metastatic NSCLC, metastatic melanoma and RCC
patients whose disease has progressed on prior anti-PD-1/PD-L1 therapy (www.clinicaltrials.gov: NCT03502330). In addition to providing
funding, Bristol-Myers Squibb will supply Opdivo and cabiralizumab, an investigational
antibody being developed in partnership with Five Prime Therapeutics.

APX005M is an investigational compound that is designed to activate CD40, a key
immune co-stimulatory receptor essential to regulating the activation of both innate
and adaptive immune responses against cancer. Cabiralizumab (FPA008) is an antibody
that inhibits colony stimulating factor-1 receptor (CSF1R) and depletes immunosuppressive
tumor associated macrophages (TAMs). Preclinical data from Yale researchers and others
have demonstrated that treatment with a combination of CD40 activation and inhibition
of CSF-1R modifies tumor-associated macrophages and activates T cells in tumors. This
results in converting a "cold" into an "inflamed" tumor microenvironment
capable of eliciting protective T cell responses in tumors that are either unresponsive
or insensitive to immune checkpoint blockade.

“There is an urgent need to find effective therapies for the growing number
of patients who have not responded to checkpoint inhibitors,” said Xiaodong
Yang, M.D., Ph.D., President and Chief Executive Officer of Apexigen. “CD40
has a fundamental role in the activation of both innate and adaptive immunity, and
we believe that CD40 activation by APX005M will become a key component of a number
of promising new I-O therapeutic regimens for treating cancer patients.”

“This most exciting collaboration between Apexigen and Yale is a result of
studies with tumor bearing mice that are poorly responsive to inhibitors of PD-1/PD-L1.
Based on these studies, we believe that activation of the innate immune system by
APX005M in combination with cabiralizumab will enhance the activity of nivolumab,
leading to a novel therapeutic approach for the increasing population of cancer patients
who progress on currently approved immune checkpoint inhibitors. This is the first
time this combination of drugs has been given to patients and we are eager to initiate
this new clinical trial,” said Harriet Kluger, M.D., Professor of Medicine at
Yale Cancer Center and Principal Investigator of the trial.

About Apexigen

Apexigen is a clinical-stage biopharmaceutical company discovering and developing
a new generation of antibody therapeutics for oncology, with an emphasis on new immuno-oncology
agents that could harness the patient’s immune system to combat and eradicate
cancer. APX005M and the Company’s additional preclinical programs were discovered
using APXiMAB™, Apexigen’s proprietary product discovery platform. This
platform has enabled the Company and its collaboration partners to discover and develop
high-quality therapeutic antibodies against a variety of molecular targets, including
targets that are difficult to drug with conventional antibody technologies. Seven
product candidates discovered using APXiMAB™ are currently in clinical development,
either internally by Apexigen or by its partners. For more information, please visit
www.apexigen.com.